fuse: simplify request abort
- don't end the request while req->locked is true - make unlock_request() return an error if the connection was aborted Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
This commit is contained in:
Miklos Szeredi
parent
ccd0a0bd16
commit
0d8e84b043
1 changed files with 46 additions and 73 deletions
119
fs/fuse/dev.c
119
fs/fuse/dev.c
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@ -382,8 +382,8 @@ __releases(fc->lock)
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{
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void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
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req->end = NULL;
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list_del(&req->list);
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list_del(&req->intr_entry);
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list_del_init(&req->list);
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list_del_init(&req->intr_entry);
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req->state = FUSE_REQ_FINISHED;
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if (req->background) {
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req->background = 0;
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@ -439,8 +439,6 @@ __acquires(fc->lock)
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/* Any signal may interrupt this */
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wait_answer_interruptible(fc, req);
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if (req->aborted)
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goto aborted;
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if (req->state == FUSE_REQ_FINISHED)
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return;
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@ -457,8 +455,6 @@ __acquires(fc->lock)
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wait_answer_interruptible(fc, req);
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restore_sigs(&oldset);
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if (req->aborted)
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goto aborted;
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if (req->state == FUSE_REQ_FINISHED)
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return;
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@ -478,22 +474,6 @@ __acquires(fc->lock)
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spin_unlock(&fc->lock);
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wait_event(req->waitq, req->state == FUSE_REQ_FINISHED);
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spin_lock(&fc->lock);
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if (!req->aborted)
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return;
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aborted:
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BUG_ON(req->state != FUSE_REQ_FINISHED);
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if (req->locked) {
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/* This is uninterruptible sleep, because data is
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being copied to/from the buffers of req. During
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locked state, there mustn't be any filesystem
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operation (e.g. page fault), since that could lead
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to deadlock */
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spin_unlock(&fc->lock);
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wait_event(req->waitq, !req->locked);
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spin_lock(&fc->lock);
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}
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}
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static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
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@ -690,19 +670,21 @@ static int lock_request(struct fuse_conn *fc, struct fuse_req *req)
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}
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/*
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* Unlock request. If it was aborted during being locked, the
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* requester thread is currently waiting for it to be unlocked, so
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* wake it up.
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* Unlock request. If it was aborted while locked, caller is responsible
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* for unlocking and ending the request.
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*/
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static void unlock_request(struct fuse_conn *fc, struct fuse_req *req)
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static int unlock_request(struct fuse_conn *fc, struct fuse_req *req)
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{
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int err = 0;
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if (req) {
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spin_lock(&fc->lock);
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req->locked = 0;
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if (req->aborted)
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wake_up(&req->waitq);
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err = -ENOENT;
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else
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req->locked = 0;
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spin_unlock(&fc->lock);
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}
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return err;
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}
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struct fuse_copy_state {
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@ -759,7 +741,10 @@ static int fuse_copy_fill(struct fuse_copy_state *cs)
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struct page *page;
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int err;
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unlock_request(cs->fc, cs->req);
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err = unlock_request(cs->fc, cs->req);
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if (err)
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return err;
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fuse_copy_finish(cs);
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if (cs->pipebufs) {
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struct pipe_buffer *buf = cs->pipebufs;
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@ -859,7 +844,10 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
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struct page *newpage;
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struct pipe_buffer *buf = cs->pipebufs;
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unlock_request(cs->fc, cs->req);
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err = unlock_request(cs->fc, cs->req);
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if (err)
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return err;
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fuse_copy_finish(cs);
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err = buf->ops->confirm(cs->pipe, buf);
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@ -949,11 +937,15 @@ static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
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unsigned offset, unsigned count)
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{
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struct pipe_buffer *buf;
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int err;
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if (cs->nr_segs == cs->pipe->buffers)
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return -EIO;
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unlock_request(cs->fc, cs->req);
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err = unlock_request(cs->fc, cs->req);
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if (err)
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return err;
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fuse_copy_finish(cs);
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buf = cs->pipebufs;
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@ -1318,7 +1310,7 @@ static ssize_t fuse_dev_do_read(struct fuse_conn *fc, struct file *file,
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fuse_copy_finish(cs);
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spin_lock(&fc->lock);
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req->locked = 0;
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if (req->aborted) {
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if (!fc->connected) {
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request_end(fc, req);
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return -ENODEV;
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}
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@ -1910,13 +1902,6 @@ static ssize_t fuse_dev_do_write(struct fuse_conn *fc,
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if (!req)
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goto err_unlock;
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if (req->aborted) {
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spin_unlock(&fc->lock);
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fuse_copy_finish(cs);
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spin_lock(&fc->lock);
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request_end(fc, req);
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return -ENOENT;
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}
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/* Is it an interrupt reply? */
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if (req->intr_unique == oh.unique) {
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err = -EINVAL;
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@ -1947,10 +1932,9 @@ static ssize_t fuse_dev_do_write(struct fuse_conn *fc,
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spin_lock(&fc->lock);
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req->locked = 0;
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if (!err) {
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if (req->aborted)
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err = -ENOENT;
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} else if (!req->aborted)
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if (!fc->connected)
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err = -ENOENT;
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else if (err)
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req->out.h.error = -EIO;
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request_end(fc, req);
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@ -2097,37 +2081,31 @@ __acquires(fc->lock)
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/*
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* Abort requests under I/O
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*
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* The requests are set to aborted and finished, and the request
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* waiter is woken up. This will make request_wait_answer() wait
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* until the request is unlocked and then return.
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* Separate out unlocked requests, they should be finished off immediately.
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* Locked requests will be finished after unlock; see unlock_request().
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*
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* If the request is asynchronous, then the end function needs to be
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* called after waiting for the request to be unlocked (if it was
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* locked).
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* Next finish off the unlocked requests. It is possible that some request will
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* finish before we can. This is OK, the request will in that case be removed
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* from the list before we touch it.
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*/
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static void end_io_requests(struct fuse_conn *fc)
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__releases(fc->lock)
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__acquires(fc->lock)
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{
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while (!list_empty(&fc->io)) {
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struct fuse_req *req =
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list_entry(fc->io.next, struct fuse_req, list);
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void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
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struct fuse_req *req, *next;
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LIST_HEAD(to_end);
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req->aborted = 1;
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list_for_each_entry_safe(req, next, &fc->io, list) {
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req->out.h.error = -ECONNABORTED;
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req->state = FUSE_REQ_FINISHED;
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list_del_init(&req->list);
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wake_up(&req->waitq);
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if (end) {
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req->end = NULL;
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__fuse_get_request(req);
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spin_unlock(&fc->lock);
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wait_event(req->waitq, !req->locked);
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end(fc, req);
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fuse_put_request(fc, req);
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spin_lock(&fc->lock);
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}
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req->aborted = 1;
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if (!req->locked)
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list_move(&req->list, &to_end);
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}
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while (!list_empty(&to_end)) {
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req = list_first_entry(&to_end, struct fuse_req, list);
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__fuse_get_request(req);
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request_end(fc, req);
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spin_lock(&fc->lock);
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}
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}
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@ -2169,13 +2147,8 @@ static void end_polls(struct fuse_conn *fc)
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* is the combination of an asynchronous request and the tricky
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* deadlock (see Documentation/filesystems/fuse.txt).
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*
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* During the aborting, progression of requests from the pending and
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* processing lists onto the io list, and progression of new requests
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* onto the pending list is prevented by req->connected being false.
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*
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* Progression of requests under I/O to the processing list is
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* prevented by the req->aborted flag being true for these requests.
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* For this reason requests on the io list must be aborted first.
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* Request progression from one list to the next is prevented by
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* fc->connected being false.
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*/
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void fuse_abort_conn(struct fuse_conn *fc)
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{
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